As shown in figure REF , consider dividing the whole boundary quantum system \(M\)  into two parts, denoted as \({M_ + }\)  and \({M_ - }\) , each of which contains large amounts of elementary regions (for simplicity, we only schematically draw four fundamental regions in each part). Let us denote the elementary regions in \({M_ + }\)  and \({M_ - }\)  as \({A_s}\)  and \({A_t}\)  respectively. Now imagine that we remove the entanglement connecting a certain elementary region \({A_s}\)  in \({M_ + }\)  with another elementary region \({A_t}\)  in \({M_ - }\) . Then this implies that the flux \({F_{st}}\)  of the qubit thread bundle \({\vec{v}_{st}}\)  characterizing this part of the entanglement is changing from a certain value to zero before and after this operation. The point is that, as we have understood from our previous discussion, the thread bundle \({\vec{v}_{st}}\)  not only contributes to the SS state of the RT surface that separates \({M_ + }\)  and \({M_ - }\) , but also contributes to the SS states of a series of RT surfaces it passes through. As shown in the figure, then, when this part of entanglement is taken away, in other words, when the flux \({F_{st}}\)  of the thread bundle \({\vec{v}_{st}}\)  becomes zero, the area of the RT surfaces that intersect with it will accordingly decrease by a value of \({F_{st}}\) . Although we still do not fully figure out how to decode the geometric information of any surface or any region in the bulk from the entanglement information in the boundary CFT states completely, however, the area changes of these RT surfaces can quantitatively characterize how the bulk spacetime shrinks as the quantum entanglement is taken away to some extent. This is very interesting. This quantitative calculation can in principle be explicitly implemented by the following formula in the locking bit thread configuration [1]}:
\(\begin{array}{l}{\rm {Are}}{{\rm {a}}_{a\left( {a + 1} \right) \ldots b}} = 4{G_N}\sum \limits _{s,t} {{F_{st}}} ,\\s \in \left\lbrace  {a,a + 1, \cdots ,b} \right\rbrace ,t \notin \left\lbrace  {a,a + 1, \cdots ,b} \right\rbrace \end{array},\) 
